This summer Samuel Gross highlighted “a terrible old rule that has done great harm to the accuracy of criminal trials, and will continue to do so.” This rule has played a significant role in preventing Jeffrey Wogenstahl from receiving justice.

Gross explains that in a criminal trial the government must disclose evidence that is favourable to the defense only if it is “material” (significant). A court determines that evidence is “material” only if it believes there is a “reasonable probability” that its disclosure would have produced a trial outcome that was more favorable to the defendant.

In other words, prosecutors may conceal evidence favourable to the defendant if they decide it is not sufficiently significant to influence the jury’s verdict.

Gross explains the bias this rule produces. Prosecutors cannot possibly know what impact the evidence in question will have on the jury; they may well be tempted to withhold the evidence to make their job easier, knowing that in all probability no one will ever know. As Gross says, “If somehow it does come out, a court reviewing the case faces the same impossible question—what might have happened at trial if these facts had been known to the defense?—with an added twist: Judges are extremely reluctant to reverse jury verdicts and order new trials.”

In Jeff’s case the prosecutors hid a huge amount of information e.g. about their witnesses, about the victim and the circumstances of her disappearance, and about other suspects. Jeff learnt about some of this relatively recently, and is fighting to get a court to consider it. No court has been troubled by the concealed evidence that Jeff discovered earlier in the appeals process (prosecutors withheld information that their key witness, Eric Horn, had trafficked drugs, even though he testified to the contrary).[i]

Gross advocates radical action to restore confidence in the judicial process: “Why not eliminate the “materiality” requirement entirely and treat access to exculpatory evidence like other aspects of a criminal defendant’s constitutional right to a fair trial? If exculpatory evidence is concealed, it’s a violation of the Constitution, period.”

We agree.

[i] Three jurors at Jeff’s trial have since signed affidavits stating that information about Eric Horn selling drugs could have altered their opinions and decisions at the trial.